Brake shoe



Nov. 22, 1927. 1,650,297

c. D. PETTIS BRAKE SHOE Filed June 5, 1,926

INVENTOQR Patented Nov. 22, 1927.

' UNITED STATES.

CLIFTO n. PETTIS, or new Yonx, n. Y.

BRAKE SHOE.

Application filedJune s, 1926. seal mans.

This invention'relates to brake shoes, and

' more particularly to: brake shoes of the type having a pressed metal shell on which. the body of the brake shoe is carried Certain forms of brake shoes haveheretotore been proposed wherein the shell ofthe brake shoe is. formed of pressed metal hav-' 111g downwardly turned; edges providing flanges on the inner face of the Shelli, and it has been proposed: to. reticulate these flanges in various ways in order tov efl'ectively unite thev plate to the body of the shoe. The body of the shoe is generally formed by placing the shell in a mold and then pouring hot 3 metal into the shell, so that the reticulated flanges are embedded in the casting, thereby intimately securing the body of the shoe tothe shell.

The present invention has for one of its objects to provide a shell having reticulated flanges wherein the perforations or reticula-. tions are so that at no time will there be a continuous straight line of se a-' ration between the metal of the flange and the cast metal body of the shoe, and wherein the metal of the flange will always be interlocked with the metal of the body until the body of the shoe has worn down to the extreme limit of usefulness.

The invention may be readily understood by reference to the accompanying drawings which illustrate apreferre'd embodiment of my invention, and in which Figure 1 is a side elevation of a shoe;

Figure 2 is a plan view of the shoe shown in Figure 1;

Figure 3 is a transverse section in the plane of line TIL-III of Figure 1;

Figure 4 is a plan View of a portion of the J blank from'which the supporting plate is formed;

Figure 5 is a diagrammatic view illustrating the manner in which the reticulated flanges and Figure 6 is a view similar to Figure 5 illustrating thesame feature when the brake shoe has been partially worn away;

Figure 7 is a diagrammatic view showing the body at the shoe worn down to approximately the limit of its usefulness illustrat ing how the cast metal is'interlocked with the pressed metal at this time; and

Figure 8 is a sideelevation'al view of a portion of brake shoe back of slightly modified form.

the cast body of the shoe inter The brake shoecomprises av supporting plate 5 having perpendicular flanges 6 on the edgesthereof. The perpendicular flanges are solid and are relatively narrow, being designed primarily to provide a Contact surface for cooperation with .the mold in which the plate'is, set when the body ofthe shoe is cast therein. The extreme inner edges 7 of the perpendicular'flanges are reticulated and are turned in laterally towardeach other so that they are convergent with respect tofeach other. Cast into. or other-wise. secured to, the shell is the body 8 of the shoe. The inturned reticulated portions 7- of the shoe are embed-- (led in the cast metal, so that. the metal extends th'rough the. reticulations thereof and is firmly interlocked therewith.

The nature of the reticulated edge may be best understood by reterence to Figure 4 showing a portion of the back plate of the shoe before it has been bent-into, shape. Arranged along each edge of the plate is are ries'of' relatively small. openings 9.. Alter natel'y disposed with respect to the small openings 9 are large openings in the form of circular notches '10. The center of curve ture' for the circular notches 1O is located along the line"AA of Figure 4:, while the centers of the circular openings 9 are on the line B B. The innermost portions of the peripheries of the circles 9 and the notches lOare on the same line, G-C, which line is tangent to the openings. The line C.@ is preferably the line on which the vertical flange 6 is bent inwardly to provide thein wardly extending flange portions 7 It will be seen from the foregoing that each inwards 1y turned flange 71 is in reality comprised of a series of inwardly turned separated fingers 11, each of which has an opening, 9 therein,

the spaces between the fingers being provided by the circular notches l0.

As thus arranged,"the cast metal is firmly secured to the shoe by reason of the fian ee and fingers 'll "being turned inwardly, as best illustrated in Figure 3. Thenietal is further united to the shoe by reason of the integral body of metal that passes through the holes 9. Since the greatest diameter of the circular notches'lO is spaced inwardly from the extreme'edge of the plate, the cast metal body is further retained in place by the portions of metal which pass through the notchesjlO, the notchesin efl'eet dovetailing or interlocking with the metal; 'As the brake shoe wears down, this interfitting or i-nterlocking will become less effective for holding the casting to the shoe, but that portion of the metal which passes through the holes 9 will still serve to effectively secure the casting to the body. As the fingers 11 wear down with the casting, a pointwill be reached eventually where the holes 9 will be half way worn down so that there will no longer be any interlocking in this respect. However, the metal will be retained finally by the transverse inward turning of the fingers or flanges. The manner in which the metal interlocks with the reticulations or fingers is well illustrated by the diagrams in Figures 5, 6 and 7. In Figure 5 the crosshatched portion represents the casting before it has worn down to the edge of the flanges or fingers. In Figure 6 the crosshatched portion represents the casting, and this figure illustrates how the partially worn away holes 9 are effective for holding the casting even after the openings 10 have been worn down past their center. Figure 7, which represents a section transverse to the views illustrated in Figures 5 and 6, illustrates how the inward curvature of the flanges or fingers will retain the cast metal even after the reticulations are not materially effective for this purpose.

Because of the fact that the holes and notches are substantially circular in the preferred form of the invention, the construction of the die for forming the blank is very simple and its upkeep is not difficult. At the same time, the circular form ofthe reticulations provides adequate interlocking between the casting and the plate. It will benoted that as the shoe wears down, there will be no time in the useful life of the shoe where there is a continuous uninterrupted line of pressed metal in the body of the casting. The fingers formed in the flanges retain their identity until the casting has been worn down to the point where it must be discarded. This is of considerable advantage in that at no time is there an entire straight line of separation through the body of the casting by reason of the inwardly turned flanges.

In the form of the invention illustrated in Figure 8, the inwardly extending edges 7 are provided with. fingers 11 spaced by openings in the form of notches 10. Within each of these fingers is an opening 9. The openings 9' and 10 form a reticulated flange or side providing, in a completed shoe, alternating zones of cast metal and sheet metal whereby the parts are effectively interlocked and the continuity of the shoe body at the sides destroyed. The zones of cast metal within the openings 10 are of gradually increasing area in the direction of wear, while the zones of cast metal within the openings 9 are of gradually decreasing area in the direction of Wear of the shoe, thus providing a condition in which the character of certain zones of metal at least partially compensates for the opposite character of other zones.

This compensating action is also true, but to a somewhat less extent, of the form of my invention first described, inasmuch as the openings ornotches 10 provide zones of cast metal which increase in area in the direction of wear until the wear line coincides with a diameter of the notch. At that time the zones of metal in the openings 9 are effective for providing gradually increasing areas until the wear line coincides with the maximum dimension thereof. here the notches are of circular shape it is desirable to have the edge of the sides or flanges 1ntersectthe same along chordal lines so located that the openings provide zones of cast metal which will first decrease in area in the direction of wear to maintain the inter lock until the other openings or series of openings come into action. I'Vith notches of other shapes the edges should intersect the same in a plane of relatively small dimension to provide a similar condition as shown in Figure 8.

When the reinforcing back or shell is curved to final shape the line CC of Fig ure l or C'C' of Figure 8 becomes an arc of a circle circumscribed around the openings. Such a circumscribed circle is tangent to all of the openings 9 and 10 and contacts with all of the openings 9 and 10. This is highly desirable as it provides a condition in which the bending line for the inturned flanges is defined, and in which the cast'bodv and the shell are intimately interlocked until the shoe has worn down to the extreme limit of usefulness. After the shoe has worn to an extent to completely wear away all of the openings, the slightly inturned edges or side flanges continue to maintain the parts in the desired position.

Another advantage of the present invention resides in the fact that the continuous solid flanges 3 give a continuous reinforcement to the plate along its entire length, and the plate at any point in its cross-section is in the form of a channel. This effectively reinforces the brake shoefand prevents it from springing or giving under the pressure of the application of the brakes, so that the shoe will always wear down evenly and uniformly and will always maintain a proper surface contact with the wheel. The bra ing pressure is applied to the shoe just above and below the lug 5 adjacent the center of the shoe. If the metal in the shoe canspring or give, this results in the center of the shoe wearing more rapidly than the ends. By reason of-the continuous channel form ofthe plate in the presentinvention, the plate will not spring and the pressure of the braking will be evenly distributed over the entire l-it) e see? surface of the shoe. Practice has demonstrated that a shoe embodying this feature will have an effective life considerably greater than'the'shoe most commonly'prov'ided in brakes at the present time, wherein the shoe can spring under braking pressure, particularly when it is partially worn down.

Further advantage arises in the particular construction illustrated from the'fact that the flanges 8, or the fingers 11 which form the flanges are bentinwardly 011 a line which is tangent to all of the reticulations 9 and 10. This makes the inward bending of the metal easier. v

I have illustrated and described a specific embodiment of my invention, but it will be understood that the invention may be otherwise embodied, and that various changes and modifications may be made within the contemplation'of my invention and under the scope of'the following claims.

I claim 1. A supporting member for a brake shoe, comprising a flanged metal plate, the flanges of which have a series of openings therein, and having a series of notches therein disposed between some of the openings.

2. A supporting member for a brake shoe,- comprising a flanged metal plate, the flanges of which have a series of openingst-here through, and having a series of notches therein, said notches'being alternately disposed between the openings.

3. A brake shoe having a metal supportingplate, flanges on each side of the plate, said flanges having a series of. spaced apart openings therein and having a series. of notches therein, disposed between the openings, the inner edges of the openings and the notches being in the same line.

4. A brake shoe having a flanged supporting plate, the flanges of which have a series of perforations therethrough, the flanges also having a series of notches therein alternately arranged with the perforations, the inner edges of the perforations and of the notches being in line.

5. A brake shoe having a flanged supporting plate, the flanges of said plate having a series of spaced apart round holes therethrough, said flanges also having a series of notches therein, said notches being disposed between some of said circular holes, the inner edges of the notches and the holes being substantially in line with one another.

6. A brake shoe having a flanged supporting plate, the flanges of which have a series of circular openings arranged therealong, said flanges also having a series of generally circular notches therein, the center line of the circularly curved notches being spaced inwardly from the edges of the flanges.

7. A brake shoe having a supporting plate which is flanged along each edge, the outer portions of the flanges being inwardly turned and having a series of circular perforations therethrough, said edge portions the flanges also having a series of circular notches therein alternately arranged with theopenings, the center line for the notches being disposed inwardly from the edge of the flange, the radius of curvature for the notches being greater than the radius of the circular openings.

8. A brakeshoc having a supporting plate which is flanged along each edge, the outer portions ofthe flanges being inwardly turned and having a series of circular perforations therethrough, flanges also having a series of circular notches therein alternately arranged, with the openings, the center line for the notches being disposed inwardly from the edge of the flange, the radius of curvature for the notches being greater than the radius of the "circular openings, the innermost points of theedges of the openings and of the notches being spaced the same distance away from the plate.

9. A brake shoe having a plate therefor, which is of channel, form, the sides of the channel being in perforate, and having a series of spaced apart fingers thereon, said fingers being. wider at their ends than they are intermediate their ends, some of the fingers having perforations therein.

10. A brake shoe having a plate herefor, which is 0,. channel form, the sides of the channel being imperforate, and having a series of spaced apart fingers thereon, said said edge portions of the fingers being wider at their ends than they are intermediate their ends, each of said fingers having a circular perforation therein, saidflngers having oppositely rounded edges.

llfA brake shoe having a plate therefor,

whichis of channel form, the sides of the channel beingimperforate, and having a series of spaced apart fingers thereon, said fingers being wider at their ends than they are intermediate their ends, each of said fingers having a circular perforation therein, said fingers having oppositely rounded edges, the inner ends of the fingers being in the same line as the innermost point of the circular perforations in the fingers.

12. A brake shoe having a pressed metal supporting plate having flanges along its edges throughout substantially its entire length, the flanges having a series of spaced apart fingers therealong, the fingers being separated by a circularly curved notch whose center line is inwardly spaced from the ends of the fingers, each of the fingers having a lit! circular perforation therein whose inner most point is in line with the innermost point of the notches between the fingers, said fingers being bent inwardly along a line which is tangential to the inner edges of the perforations and notches.

13. A brake shoe constructed to provide alternating zones of cast metal and sheet metal in the side portions thereof, at least the zones of cast metal being of changing area in the direction of wear and so arranged that the decreasing area in the direction of wear of certain of said zones is at least partially compensated by the increasing area in the direction of wear of other of said zones.

14:. A brake shoe constructed to provide alternating zones of cast metal and sheet metal in the side portions thereof, at least the zones of cast metal being of changing area in the direction of wear and so arranged that the decreasing area in the direction of wear of certain of said zones is, at least par tially compensated by the increasing area in the direction of wear of other of said zones, all of said openings being of circular contour.

15. A reinforcing means for brake shoes, comprising a body with angularly extending sides, each having a plurality of openings so located that a line tangent to at least two of said openings is tangent to the major number of said openings.

16. A reinforcing means for brake shoes, comprising a body with convergently extending sides, each having a plurality of openings so located that a line tangent to at least two of said openings is tangent to all of said openings.

17 A reinforcing means for brake shoes, comprising a body with angularly extending sides, each having a plurality of openings of different diameters overlapping in the direction of wear of the. shoe.

18. A reinforcing means for brake shoes, comprising a body with angularly extending sides, each having a plurality of openings of different diameters overlapping in the direction of wear of the shoe and all lying within a circumscribed circle tangent to any two of said openings.

19. A reinforcing means for brake shoes, comprising a body with angularly extending sides, each having a plurality of openings of different diameters overlapping in the direction of wear of the shoe, all of said openings being of circular contour.

20. A reinforcing means for brake shoes, comprising a body having sides formed by a plurality of fingers formed by openings of one size, with an opening of different size in each finger. 7

21. A reinforcing means for brake shoes, comprising a body with sides having openings therein overlapping in the direction of wear, the edges of the sides intersecting certain of said openings only, the line of intersection coinciding with chordal lines of said openings to provide zones of metal therein of increasing area in the direction of wear for at least a predetermined distance.

22. A metal back for brake shoes having a flange thereon, said flange being provided with a series of openings therein and with a series of notches disposed between at least some of the openings, said openings and notches overlapping in such manner as to be eifective in a common line equidistantly spaced from said back throughout its length.

23. A reenforcing means for brake shoes.

comprising a body with angularly extending portions, each having a plurality of series of openings therein, with the openings of the different series overlapping in the direction of wear of the shoe, all of said openings being so arranged that a common circle may be described passing through all of the openings of both series but at different distances from the centers of the openings of the respective series.

In testimony whereof I have hereunto set my hand.

CLIFTON D. PETTIS. 

